Gen VI has been very kind to Zoroark overall. Thanks to the Steel-type nerf and Knock Off buff, what was once a Pokemon that lived and died by its gimmick is now one of the fastest STAB users of one of the better offensive types in the game. Zoroark is now less reliant on coverage and is much harder to switch into. However, as is often the case, it's not all good news for the Illusion Fox. Zoroark still takes hits like a wet paper bag and, while not as common as Steel-types, the new Fairy-type Pokemon wall Zoroark with ease, which is a bitter trade for Steel-type neutrality. While Steel-types were bested by a well-placed Low Kick or Flamethrower, there are really no options for Zoroark to overcome Fairy-type Pokemon. But even with such obstacles, Zoroark can be a volatile threat in OU with correct use of Illusion combined with its naturally powerful Dark-type STAB attacks.
name: Swords Dance
move 1: Swords Dance
move 2: Knock Off
move 3: Sucker Punch
move 4: Low Kick
item: Focus Sash / Life Orb
evs: 252 Atk / 252 Spe / 4 HP
Knock Off and Sucker Punch ensure that Zoroark packs a punch no matter what the Speed of the opponent is. Sucker Punch is the more powerful attack against Mega Evolutions, as Knock Off does not get its Base Power boosted. Low Kick allows Zoroark to nail opposing Dark-types as well as hit Heatran harder.
The ideal use for this set is to use Illusion to net a Swords Dance, then sweep with a Focus Sash to support it. However, Illusion isn't always reliable, so it will commonly be using Focus Sash to get the Swords Dance it needs. However, if your team packs particularly threatening or convincing Illusions, a Life Orb can be used to have Zoroark muscle its way past bulky sweepers such as Garchomp. A Jolly nature allows Zoroark to avoid playing games with Pokemon that run Substitute such Landorus as well as potentially avoiding Mega Pinsir's Quick Attack moving first and nullifying Sucker Punch.
Zoroark's physical movepool is horrid and the one other move that would be decent, U-turn, is counterproductive with Swords Dance. Low Kick is very much needed to not be walled by fellow Dark-types such as Bisharp and Tyranitar. Packing Defog or Rapid Spin onto a team is a necessity for using Focus Sash. It is also very important to keep in mind that Illusion is a tool, not a necessity. Zoroark is plenty scary by itself with high Speed and powerful Dark-type STAB alone. Seriously, never compromise an advantageous situation just to give Zoroark's Illusion a better chance of fooling the opponent later.
Terrakion makes a fantastic Illusion and lures Gliscor in for a Knock Off. Skarmory can use both Defog and Stealth Rock, while Latios and Latias can also Defog and make for great Illusions. If using Life Orb, the damage Zoroark takes from Stealth Rock is very important to having a convincing Illusion. Focus Sash demands Defog or Rapid Spin support, so hazards should be a non-issue for that variant. Mega Venusaur is a fantastic Pokemon that covers Zoroark's weaknesses and makes for a decent Illusion as well. Any Pokemon that can lure in and KO Fairy- or Fighting-types are welcomed as it can't be stressed enough that Zoroark is hard walled by Fairy-types. Additionally, having Zoroark appear as powerhouses like Pinsir forces the opponent to take action which can net free turns to Swords Dance or force and opponent like Aegislash to attack and try to prevent the Pinsir from Swords Dancing instead of scouting for Zoroark's Knock Off.
Mixed sets can potentially work well with STAB Sucker Punch backed up by Zoroark's decent special movepool. Nasty Plot may be tempting, but many common OU Pokemon can outpace Zoroark, and Zoroark lacks any special priority moves to hit them with. Purely special attacking sets are generally inferior to sets with Knock Off, but they have a larger coverage movepool as well as Dark Pulse's flinch rate to help them. Focus Blast can nail Dark-types on special attacking sets, but a missed attack can easy spell the end of Zoroark. Night Daze is a mere 5 Base Power more powerful than Dark Pulse but trades a 20% flinch rate and 100 accuracy for 95 accuracy and a 40% chance to drop opponent's accuracy one stage.
Checks and Counters
**Being Careful of Illusion**: Zoroark's ability, Illusion, makes it harder to counter than similar Pokemon and intelligent use of it can make for very awkward situations if battling a Zoroark.
**Fairy-types**: Most Fairy-type Pokemon wall Zoroark hard and are at best hindered by a Knock Off.
**Bulky Dark-types**: Bulky Dark-types, especially Mandibuzz and Sableye, can pose as huge obstacles to Zoroark if Low Kick cannot hit them super effectively.
**Mega Evolutions**: Bulky Mega Evolutions such as Mega Venusaur, Mega Pinsir, defensive Mega Charizard X, and Mega Heracross can give physical Zoroark trouble, as Knock Off has only 65 base power against them.
**Exploiting its Lack of Defenses**: Zoroark is so frail that most offensive Pokemon can OHKO Zoroark with an unresisted STAB attack, so if you can figure out Zoroark's game and not get slammed by Sucker Punch, it's not too hard to manage against it.